1. Field of the Invention
The present invention is a jig for performing a cross hatching test, and more specifically, it is a jig for performing a cross hatching test which is applied for adhesiveness measurement of all kinds of coating materials such as thin film, ink and the like.
2. Description of the Background Art
A test for checking adhesive strength of thin film, ink and the like (referred to as "paint film" hereinafter) usually includes a cross-cut adhesion test, a salt spray test, etc.
In the cross-cut adhesion test, a paint film is formed on a rectangular sample piece (referred to as "test plate" hereinafter) of predetermined dimensions, and a lattice layout of cuts is made through the paint film up to the base of the test plate with a sharp-edged tool, so that fragility of the paint film and propriety of its adhesiveness to the base may be estimated from flaws extended from the cuts (JIS K 5400). Specifically, a designated strip of adhesive tape or the like is affixed to the paint film which has cuts in it in a lattice layout, and pulled off in a direction orthogonal to the test plate, and then the paint film which has been peeled away is compared with a reference photograph or the like in order to evaluate the adhesive strength by comparing various points of the peeling.
On the other hand, in the salt spray test, a paint film is formed on a test plate similar to that used in the above test, and a cross-cut layout (60.degree., 30.degree.) of scars is made through the paint film up to the base of the test plate with a sharp-edged tool. The test plate is placed in a device for generating a salt water fog (a device prescribed by JIS Z 2371) for the primary purpose of determining whether the fog of salt water acts on the paint film to make it rusty or swollen (JIS K 5400).
Usually, the above-mentioned two tests are applied to the same paint film at the same time. Thus, it is expedient that a jig for these tests has both slits for making cuts in the cross-cut adhesion test and with lines for making cross-cuts in the salt spray test, on the same plate.
When making the cross-cuts utilizing the jig, it is necessary to position an intersection in the center of the test plate and insure that the cross-cuts are almost uniformly laid out on the test plate. The accuracy of this procedure is always quite dependent upon the perception of the operator.
With the test applied under such circumstances, reproducibility of the cross-cuts declines and the test results suffer due to non-uniformity.